Someone pointing out a big glaring exception to your generalization isn’t “whataboutmeism” it’s just someone pointing out a flaw in your argument. If you said “everyone who can’t walk up a flight of stairs is a lazy pos” and a bunch of people tell you that they can’t because they’re disabled you can’t go “well OBVIOUSLY I don’t mean you” because like. Most people who can’t walk up a flight of stairs are disabled. Its not obvious at all that you don’t mean them actually